1. Field of the Invention
The present invention relates to an electrophotography image forming apparatus, such as a copier, a printer, a facsimile machine, or a multifunction peripheral including the copier, the printer, and the facsimile machine, and in particular, to an image forming apparatus including a neutralizing light source for neutralizing a surface potential on an image bearer, such as a photoconductor drum.
2. Description of the Related Art
Conventionally, in an image forming apparatus such as a copier or a printer, a technique in which a neutralizing light source that neutralizes a surface potential on an image bearer such as a photoconductor drum or a photoconductor belt, is provided at a position downstream of a transfer position and upstream of a cleaning unit, rather than at a position downstream of the cleaning unit and upstream of a charging unit, so as to face the image bearer, has been widely used (see, for example, Japanese Patent No. 5327569, Japanese Laid-open Patent Publication No. 2011-112818, and Japanese Laid-open Patent Publication No. 2003-122065).
Specifically, in Japanese Patent No. 5327569, a neutralizing lamp (neutralizing light source) is provided at a position downstream of a transfer position in a rotation direction of a photoconductor drum (image bearer) and upstream of a cleaning device (cleaning unit) in the rotation direction of the photoconductor drum so as to face the photoconductor drum. The surface of the photoconductor drum is directly irradiated with neutralizing light emitted from the neutralizing lamp, and a surface potential on the photoconductor drum is neutralized.
Further, to reduce a defect such as light deterioration of a photoconductor drum due to the neutralizing light emitted from the neutralizing lamp, Japanese Patent No. 5327569 discloses a technique in which the light intensity of the neutralizing light emitted from the neutralizing lamp is changed in accordance with a timing of changing a transfer bias.
Meanwhile, Japanese Laid-open Patent Publication No. 2011-112818 and Japanese Laid-open Patent Publication No. 2003-122065 disclose techniques in which a first neutralizing light source is provided downstream of a cleaning unit and upstream of a charging unit so as to face a photoconductor drum (image bearer), and a second neutralizing light source is provided downstream of a transfer position and upstream of the cleaning unit so as to face the photoconductor drum.
In the conventional techniques, the surface of the image bearer (photoconductor drum) is directly irradiated with the neutralizing light; therefore, a defect such as acceleration of light deterioration of the image bearer occurs.
In this regard, in the technique described in Japanese Patent No. 5327569, the light intensity of the neutralizing light emitted by the neutralizing lamp is changed according to a timing of changing a transfer bias, and therefore, it is expected that a defect as described above is reduced to some extent. However, in the technique described in Japanese Patent No. 5327569, control of changing the light intensity of the neutralizing light may become complicated.
In view of the above, there is a need for an image forming apparatus capable of reducing a defect including acceleration of light deterioration of an image bearer due to neutralizing light emitted by a neutralizing light source, with a relatively simple configuration and control.